1. Field of the Invention
The invention relates to a video signal processing circuit for processing at least a first and a second video signal, the circuit comprising a field memory circuit a first switching device operable by means of a time selection signal for writing the first and the second video signals into a first and a second section, respectively, of the field memory circuit corresponding to a first and a second part, respectively, of a picture to be displayed, and a second switching device
2. Description of Related Art
A video signal processing circuit of the type described above is known from European patent Specification EP-B 0,111,374 in which the field memory circuit is used as a field frequency doubling circuit for the video signals. The first video signal is used for obtaining a normal television picture and the second video signal is used for obtaining, for example, a sub-title in this television picture. The time selection signal then determines the position of the subtitle. The second switching device is present at the output of the field memory circuit and is operated by a further time selection signal which corresponds to the previously mentioned time selection signal which has been doubled in field frequency. The second switching device prevents the second video signal from being conveyed via a digital-to-analog converter circuit which is required for converting the first video signal.